It’s a hedge fund savvy enough to have scooped up Bitcoin when it was free. One of its founders is the well-known CEO of AngelList, Naval Ravikant. It’s backed by a roster of Silicon Valley’s top venture capital firms, and boasts returns of more than 500%. And you’ve probably never heard of it. Meet MetaStable Capital, a stealthy startup hedge fund based in San Francisco that invests only in cryptocurrencies such as Bitcoin and Ethereum. Since its launch in September 2014, MetaStable has delivered such eye-popping performance that it apparently lets the numbers mostly speak for themselves; it shuns publicity and never announced its recent fundraising round.

Still, Fortune has learned many of the details. In the spring, Andreessen Horowitz, Sequoia Capital, Union Square Ventures, Founders Fund and Bessemer Venture Partners all invested in MetaStable, according to several of the VCs and other people close to the fund. [ Fortune ]